History is sometimes written by neither the winners nor the losers, but by the invisible transcribers and administrators - like Hitler’s secretary Traudl Junge in Downfall (2006), or autopsy attendant Mario Cornejo in Pablo Larraín’s bleak, disturbing Post Mortem.

This third feature film from the young Chilean director revisits the 1970s Santiago of Tony Manero (2007), his story of a Saturday Night Fever-obsessed loner, but sets the scene some years earlier, in the midst of the 1973 military coup that installed Augusto Pinochet as the country’s leader. The films are superficially alike: the solitary Mario is played by Alfredo Castro, who, as ageing Travolta lookalike Raúl, provided Tony Manero‘s dark heart; once again, cinematographer Sergio Armstrong gives a grainy, deliberately faded hue to the various shabby settings. But where Tony Manero, with its story of talent contests and disco fans, offers some moments of release - we respond to rhythm and sound, dance and music, however twisted and clichéd - Post Mortem is unrelentingly, often distressingly, slow and even static.

Larraín’s restraint isn’t just a stylistic affectation, though. It is entirely appropriate, creating an atmosphere of quiet horror and incipient crisis, and reflecting the morbid, flat world of his new protagonist. Mario, who describes himself as a ‘functionary’, is surrounded by death: his job is to type up autopsy reports at the local morgue. His neighbour, Nancy (Antonia Zegers), is a cabaret dancer with whom he develops a sexual obsession that turns into a vague affair. She is painfully thin, whether through poverty or anorexia isn’t clear. In the background of this, far from the screen, the momentous events of a revolution are occurring and, as Nancy’s family of socialist activists disappear overnight, Mario is called upon to transcribe at the autopsy of ousted president Salvador Allende and finds his department swamped with dead and dying victims of the military, slumped on and toppling off over-stacked trolleys. It is made clear that he now works for the new regime.

In other hands, these events might be the catalyst for heroic acts, or feelings of resistance, or at least some kind of sympathetic character development. But Mario moves among the corpses with morose detachment, impervious to his colleague Sandra’s distress, his main preoccupation still Nancy, who tries to elicit his help in hiding her from the authorities. As the city locks down into the fearful silence of dictatorship, Larraín keeps the action tightly focused on his small cast, closing in on a claustrophobic, macabre ending that works as a neat summary of all the deprivation and cruelty that has led up to it.

While it’s hardly a dialogue-led film, some omissions and errors in Post Mortem‘s subtitling will perhaps prompt non-Spanish-speaking viewers to concentrate most on the film’s considerable visual impact. But there is a sense anyway that language fails in crisis, leaving us little choice but to focus on the very fact of the body: its needs, its responses, and the ease with which it can be damaged and obliterated by others. The only criticism of Larraín’s confident and brutal minimalism might therefore be that it’s hard to see where he could go next with this subject matter, and perhaps with this cast and crew; but I will be watching whatever he and Alfredo Castro do next, however harsh.